The present invention is directed to compounds which modulate interleukin-1 (IL-1) receptor-associated kinase 4 (IRAK4) and are useful in the prevention or treatment of inflammatory, cell proliferative and immune-related conditions and diseases.
The recruitment of immune cells to sites of injury involves the concerted interactions of a large number of soluble mediators. Several cyctokines appear to play key roles in these processes, particularly IL-1 and TNF. Both cytokines are derived from mononuclear cells and macrophages, along with other cell types. Physiologically, they produce many of the same proinflammatory responses, including fever, sleep and anorexia, mobilization and activation of polymorphonuclear leukocytes, induction of cyclooxygenase and lipoxygenase enzymes, increase in adhesion molecule expression, activation of B-cells, T-cells and natural killer cells, and stimulation of production of other cytokines. Other actions include a contribution to the tissue degeneration observed in chronic inflammatory conditions, such as stimulation of fibroblast proliferation, induction of collagenase, etc. They have also been implicated in the process of bone resorption and adipose tissue regulation. Thus, these cytokines play key roles in a large number of pathological conditions, including rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, diabetes, obesity, cancer, sepsis, etc.
The importance of IL-1 in inflammation has been demonstrated by the ability of the highly specific IL-1 receptor antagonist protein (IL-1Ra or IRAP) to relieve inflammatory conditions. See, e.g., Dinarello, Cytokine Growth Factor Rev., 1997, 8:253-265.
IL-1 treatment of cells induces the formation of a complex consisting of the two IL-1 receptor chains, IL-1R1 and IL-1RAcP, and the resulting heterodimer recruits an adapter molecule designated as MyD88. See e.g., Wesche et al., J. Biol. Chem., 1999, 274:19403-19410. MyD88 binds to a protein designated IRAK (IL-1 receptor associated kinase). See, e.g., O'Neill et al., J. Leukoc. Biol., 1998, 63(6):650-657; Auron, Cytokine Growth Factor Rev., 1998, 9(3-4):221-237; and O'Neill, Biochem. Soc. Trans., 2000, 28(5):557-563. IRAK is subsequently phosphorylated and released from the receptor complex to interact with a tumor necrosis factor receptor-associated factor, TRAF6, which transduces the signal to downstream effector molecules. See e.g., Cao et al., Nature, 1996, 383:443-446. TRAF6 can trigger the NIK/IKK kinase cascade to activate the transcription factor NK-kappa B. NF-kappa B regulates a number of genes that, in turn, regulate immune and inflammatory responses.
Four IRAKs have been identified: IRAK1 (see, e.g., Cao et al., Science, 1996, 271:1128-1131), IRAK2 (see, e.g. Muzio et al., Science, 1997, 278:1612-1615), the monomyeloic cell specific IRAKM, also known as IRAK3 (see, e.g., Wesche et al., J. Biol. Chem., 1999, 274:19403-19410), and IRAK4 (see, e.g., PCT Publication No. WO 01/051641). IRAK proteins have been shown to play a role in transducing signals other than those originating from IL-1 receptors, including signals triggered by activation of IL-18 receptors (see, e.g., Kanakaraj et al., J. Exp. Med., 1999, 189(7):1129-1138) and LPS receptors (see, e.g., Yang et al., J. Immunol., 1999, 163:639-643; and Wesche et al., J. Biol. Chem., 1999, 274:19403-19410). Over-expression of IRAK2 and IRAKM has been shown to be capable of reconstituting the response to IL-1 and LPS in an IRAK deficient cell line.
The identification of compounds that inhibit the function of IRAK4 represents an attractive approach to the development of therapeutic agents for the treatment of inflammatory, cell proliferative and immune-related conditions and diseases associated with IRAK4-mediated signal transduction, such as rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, diabetes, obesity, allergic disease, psoriasis, asthma, graft rejection, cancer, and sepsis.
It is an object of the instant invention to provide novel compounds that are inhibitors of IRAK4.
It is also an object of the present invention to provide pharmaceutical compositions that comprise the novel compounds that are inhibitors of IRAK4.
It is also an object of the present invention to provide a method for treating IRAK4-mediated and associated conditions or diseases that comprises administering such inhibitors of IRAK4 activity.